New insights on equid locomotor evolution from the lumbar region of fossil horses
New insights on equid locomotor evolution from the lumbar region of fossil horses
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DOI：
10.1098/rspb.2015.2947
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发表时间：
2016-04-27
影响因子：
4.7
通讯作者：
Jones, Katrina Elizabeth
中科院分区：
文献类型：
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作者：
Jones, Katrina Elizabeth
马类动物的四肢因其奔跑能力而特化，是适应性进化的一个经典案例，但中轴骨骼在这一著名的转变中所扮演的角色，人们还没有很好地理解。现存的马是非常快速和高效的跑步者，它们使用僵硬的背部奔跑，相对于其他哺乳动物，腰部的弯曲减少。本研究测试的假设，即在马的硬背运行进化的身体尺寸的进化增加，通过检查腰关节形状从一个广泛的样本化石马科动物在系统发育的背景下。腰椎关节形状缩放表明腰椎区域的稳定性确实通过等时进化与尺寸相关。然而，缩放效应在后腰椎区域（靠近骶骨）减弱，这表明腰骶关节附近与运动-呼吸耦合相关的矢状移动性具有较强的选择性。我推测，小型化石马可能使用了一种依赖于速度的跑步步态，随着速度的增加，在僵硬的背部和弯曲的背部之间切换。
The specialization of equid limbs for cursoriality is a classic case of adaptive evolution, but the role of the axial skeleton in this famous transition is not well understood. Extant horses are extremely fast and efficient runners, which use a stiff-backed gallopwith reduced bending of the lumbar region relative to other mammals. This study tests the hypothesis that stiff-backed running in horses evolved in response to evolutionary increases in body size by examining lumbar joint shape from a broad sample of fossil equids in a phylogenetic context. Lumbar joint shape scaling suggests that stability of the lumbar region does correlate with size through equid evolution. However, scaling effects were dampened in the posterior lumbar region, near the sacrum, which suggests strong selection for sagittal mobility in association with locomotor-respiratory coupling near the lumbosacral joint. I hypothesize that small-bodied fossil horses may have used a speed-dependent running gait, switching between stiff-backed and flex-backed galloping as speed increased.